Method and an apparatus for turning boards

ABSTRACT

A method of turning boards ( 2 ) comprises the steps that the boards ( 2 ) are transported on a conveyor ( 1 ) with conveyor dogs ( 4 ), with their longitudinal direction transverse to the conveyor ( 1 ). The boards ( 2 ) are accelerated relative to the conveyor ( 1 ) until the front edges ( 13 ) of the boards ( 2 ) abut against the rear edge ( 14 ) of the next dog ( 4 ). Lifting devices ( 16 ) which move synchronously with the conveyor ( 1 ) lift the front edges of the boards ( 2 ) at the same time as the boards ( 2 ) are moved towards the lifting devices ( 16 ), whereby the boards ( 2 ) are turned with their front edges facing upwards and backwards. An apparatus for turning boards comprises a first conveyor ( 1 ) with dogs ( 4 ) for transport of the boards ( 2 ), and a second conveyor ( 11 ) with an upper part ( 12 ) which, on the first conveyor ( 1 ), shunts the boards from one dog ( 4 ) to the next. The lifting devices ( 16 ) are disposed to move synchronously with the first conveyor ( 1 ) and gradually to be raised immediately behind the dogs ( 4 ) of the first conveyor.

TECHNICAL FIELD

The present invention relates to a method of turning boards which aretransported with their longitudinal direction transverse to thedirection of movement of a conveyor with uniformly spaced conveyor dogs,the boards being at least partly driven by the front sides of the dogsin abutment against the rear edges of the boards.

The present invention also relates to an apparatus for turning boardsand comprises a first conveyor with uniformly spaced conveyor dogs fortransport of the boards with their longitudinal direction transverse tothe direction of movement of the conveyor.

BACKGROUND ART

In the refining of timber in the form of boards in sawmills, planingmills, furniture factories or the like, it is often necessary that theboards be turned upside down between different working operations or inorder to carry out quality inspection. Situations also arise when onlycertain boards in a batch are to be turned over. Such turning of boardshas hitherto largely been carried out manually.

PROBLEM STRUCTURE

The present invention has for its object to devise the method disclosedby way of introduction such that it permits a fully automatic turning ofthe boards upside down. The present invention also has for its object todevise the method such that only certain boards included in a batch areturned over. The present invention further has for its object to devisethe method such that the boards may be handled at great speed and with ahigh degree of reliability without being damaged.

The present invention also has for its object to design the apparatusintimated by way of introduction such that it is capable of turning allor only certain boards included in a batch at great speed and with ahigh degree of reliability, that the apparatus is simple andoperationally reliable and is also economical in manufacture and inoperation.

SOLUTION

The objects forming the basis of the present invention in respect of themethod will be attained if the method is characterized in that theboards are moved forwards in a direction of movement in relation to theconveyor such that the front edges of the boards are brought to theregion of the rear side of the next dog in the conveyor, that liftingdevices which are moved synchronously with the conveyor are brought intoengagement with the undersides of those boards which are to be turned inthe region at their front edges, that the lifting devices are graduallyraised, and that the boards are subjected to a force in relation to thelifting devices forwardly in their direction of movement, whereby theboards are caused to turn over with their front edge facingupwards/rearwards.

The objects forming the basis of the present invention in respect of theapparatus will be attained if this is characterized by at least onesecond conveyor which is substantially parallel with the first and hasan upper part at a slightly greater height than the upper part of thefirst conveyor, the second conveyor operating at greater speed ofmovement that the first, and a number of lifting devices which aredisposed to move synchronously with the first conveyor and to beliftable in the region behind the dogs of the first conveyor.

Further advantages will be attained according to the present inventionif the method is also given one or more of the characterizing featuresin and if the apparatus is given one or more of the characterizingfeatures.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will now be described in greater detailhereinbelow, with reference to the accompanying Drawings. In theaccompanying Drawings:

FIG. 1 schematically illustrates and apparatus for turning boards, seenfrom the side, i.e. in the longitudinal direction of the boards; and

FIG. 2 is a top plan view of the same apparatus as in FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT

The apparatus according to the invention comprises a first conveyor 1which is intended for transporting boards 2 in a transport direction 3,from the right to the left in the Figures. The first conveyor has anumber of uniformly spaced dogs 4 which, with their front sides 5, shuntthe boards ahead of them in engagement with the rear edges 6 of theboards. In such instance, transport of the boards 2 takes place with thelongitudinal direction of the boards transverse to the longitudinaldirection of the first conveyor and transverse to the transportdirection 3. Preferably, the longitudinal directions of the boardsextend at right angles to both the transport direction 3 and thelongitudinal direction of the conveyor 1.

The first conveyor may include a number, preferably at least two, ofparallel-running chains, straps, belts or the like which are providedwith the above-disclosed dogs. The number of such chains etc., dependson the length of those boards which are to be transported. FIG. 2 showstwo such chains or the like.

The chains, straps or belts included in the first conveyor 1 run overwheels 7 and 8 which are supported on rotary shafts 9 and 10.

In addition to the chains, straps or belts included in the firstconveyor, this conveyor may further include a number of longitudinally(along the transport direction 3) disposed slide rails which verticallysupport the boards 2 being transported. Instead of, or as a supplementto such slide rails, the chains etc. in the first conveyor may possiblyhave their upper regions supported in longitudinal guides which may alsocarry the weight of the boards.

The above disclosures as regards the cooperation of the first conveyorwith the advanced boards applies at the infeed end of the conveyor andat its discharge end, i.e. at its right-hand and left-hand end,respectively. Along the central region of the conveyor, i.e. along aturning zone, the situation is different in that the first conveyor hereat least partly functions as a brake which prevents the boards 2 in thetransport direction 3 from being displaced past predetermined positions,as will be described in greater detail hereinbelow.

Within the turning zone, there is provided a second conveyor 11 which isalso designed as a chain conveyor, strap conveyor or belt conveyor orthe like. The second conveyor suitably has the same number of chains,straps or belts as the first conveyor, and these are disposed along andsubstantially parallel with the corresponding chains etc. in the firstconveyor 1. The number of such chains etc. is adapted to the length ofthe boards 2 in the same manner as that which applies to the firstconveyor.

The second conveyor 11 has its upper part 12 located at a slightlygreater height than the upper part of the first conveyor 1. Further, thechains, straps or belts in the second conveyor are of a material whichaffords good friction against the boards 2. Hereby, the second conveyor(which advances at a greater transport speed than the first conveyor 1)will subject the boards to a force in the transport direction 3 relativeto the first conveyor. This implies that the boards 2 within the turningzone, i.e. the longitudinal extent of the second conveyor 11, will begiven higher speed by the second conveyor, so that the boards, withtheir front edges 13, will come into abutment against the rear edge 14of the immediately preceding dog 4. This is clearly apparent at theright-hand end of the second conveyor 11 in FIG. 1.

That disclosed above in respect of the slide rails, longitudinal guidesetc. in connection with the first conveyor 1 applies with equal analogyalso to the second conveyor 11. It should also be observed that,regardless of the detailed design of these slide rails, guides, etc., itapplies that the second conveyor carries the boards 2 at a height levelwhich is slightly higher than the first conveyor.

The width of the open space between adjacent dogs 4 on the firstconveyor 1 is, for reasons which will be apparent below, approximatelytwice as large as the maximum width of the boards 2 which are to beturned.

Within the turning zone, i.e. within the longitudinal extent of thesecond conveyor 11, there is provided a third conveyor 15. This isdisposed along and beside the first conveyor 1 and preferably has thesame number of chains, straps, belts or the like as the first conveyor.The third conveyor 15 is provided with a number of lifting arms orlifting devices 16 which move synchronously with the first conveyor inits transport direction 3. The lifting devices 16 are disposed behindthe rear edges 14 of the dogs 4 and are disposed to be liftable withinthe turning zone.

In such cases where all boards 2 are to be turned, the lifting devices16 may be fixedly disposed on the third conveyor 15 in positionsrelative thereto which are shown along the upper part of the thirdconveyor 15 in FIG. 1. This implies that, because of the upwardinclination in the transport direction 3, the lifting devices 16 will begradually raised within the turning zone.

In such cases where only certain boards 2 included in a batch are to beturned, the lifting devices 16 are movably disposed on the thirdconveyor 15, as will be described in greater detail hereinbelow.

It will be apparent from FIG. 1 that a lifting device 16 a has just comeinto engagement with the underside of a board which, with its frontedge, abuts against the rear edge 14 of a dog 4. The next lifting device16 b has raised the front portion of the board up and begins to turn theboard over, with its front edge facing backwards. This turning of theboard is facilitated by the fact that the second conveyor 11 subjectsthe board to a force in the direction of the transport direction of thefirst conveyor, i.e. in the direction of the arrow 3. This force isgenerated by the second conveyor 11 in that this moves more quickly thanthe lifting devices 16 so that the boards are shunted against thelifting devices. As a result of this force, the turning or rotation ofthe board about its longitudinal axis is facilitated and supported. Thelifting device 16 c has just raised the front edge of the board so highthat the board loses its balance and is pivoted down backwards on theconveyor 11. For this backward pivoting of the board to be possible, thedistance between adjacent dogs 4 should be approximately twice as largeas the maximum width of turned boards. It will further be apparent fromFIG. 1 that the lower edge of the board, which rests on the secondconveyor, has been displaced in the direction of the arrow 3, for whichreason the lifting device 16 c no longer engages with the front edge ofthe board, now turned to face upwards, but instead with the centralportion of the original underside of the board.

Once the board has been finally turned upside down by the lifting device16 c, it will once again be given increased speed in relation to thefirst conveyor 1, which is shown straight above the drive wheel 17 ofthe second conveyor 11.

The third conveyor 15 is carried by shafts 18 and 19 which are locatedat different heights so that the upper part of the third conveyor willthereby slope upwards in its direction of movement, whereby the liftingdevices 16 which follow the upper part of the third conveyor willgradually be raised.

In order to permit turning of only certain boards included in a timberbatch, the lifting devices 16 are suitably not permanently fixed inrelation to the third conveyor 15, but are secured in sleeves 20 whichhave their longitudinal axes parallel with the parts of the thirdconveyor 15. The lifting devices 16 are pivotal in these sleeves, forwhich reason the lifting devices 16 a, 16 b and 16 c are pivotal inaccordance with the double headed arrow 21 about the pivot axis 24.Along the lower part, the lifting devices 16 are naturally pivotal in acorresponding manner about an axis which is parallel with the lower partof the conveyor.

The anchorage of the lifting devices 16 in the sleeves 20 disposed onthe third conveyor is pivotal and without defined stops, for example inthat the lifting devices have conical portions which, under spring bias,are axially pressed into corresponding conical apertures in the sleeves20.

At the return areas of the third conveyor 15, there are provided guiderails or guides 22 and 23, where the guide 23 is disposed to open outthe lifting devices 16 which, along the lower part of the conveyor, arecollapsed to a state approximately parallel with the shafts 18 and 19,to outwardly pivoted activated, upstanding positions which are shownalong the upper part of the conveyor. The guide 23 is movable between anactive and opened position where it pivots out the lifting devices 16and a passive, collapsed position where the lifting devices may passwithout hindrance and without being pivoted out to the active positionswhich are shown along the upper part of the third conveyor. The guide 23is coupled to a suitable prime mover for permitting pivoting of all oronly certain of the lifting devices, corresponding to turning of allboards or only certain boards, respectively.

The guide 22 at the upper end of the third conveyor is designed foropposite pivoting of the lifting devices 16, i.e. for downward pivotingof them from the upstanding, active positions along the upper part ofthe conveyor to collapsed, substantially horizontal positions along thelower part of the conveyor.

The above-described apparatus operates as follows:

Boards 2 are fed in at the right-hand end of the first conveyor 1 andrest thereon or along slide rails or guides disposed with the conveyor.The boards 2 are driven by the conveyor 1, at least along a certain partof its length, in that the rear edges 6 of the boards abut against thefront sides 5 of the dogs 4 of the conveyor 1. When the boards 2 havearrived at the turning zone, i.e. the longitudinal extent of the secondconveyor 11, the boards are displaced forwards in the transportdirection 3 in relation to the first conveyor 1. In such instance, thefront edges 13 of the boards will strike the rear edges 14 of the dogs 4and be held urged against them, at least along a certain portion ofmovement length of the second conveyor. The lifting devices 16 arebrought into engagement with the undersides of the boards 2 in theregion of their front edges 13. The lifting devices 16 are disposed tomove synchronously with the first conveyor 1 and are located in theregion immediately behind, or at least in the proximity behind the rearedges 14 of the dogs 4. Those lifting devices 16 which are to turnboards are disposed to be raised gradually so that the font edgeportions of the boards 2 are thereby lifted up. At the same time, theboards are subjected to a force relative to the first conveyor and thelifting devices, the direction of this force corresponding to thetransport drive direction 3 of the first conveyor. Hereby, the boards 2will be displaced in the transport direction at the same time as theirforward edge portions are lifted and braked and their rear/lower edgeswhich rest on the upper part 12 of the second conveyor 11 are subjectedto a shunting force so that the boards are thereby turned over withtheir front edges facing upwards and backwards so far that the boardsare tilted backwards, with the original upper side facing downwards onthe upper part 12 of the second conveyor 11.

In order to ensure the above-mentioned engagement or force between theboards 2 and the upper part 12 of the second conveyor 11, the boards arelifted by this upper part in relation to the level of the upper part ofthe first conveyor 1.

Once the lifting devices 16 have turned the boards, they are once againlowered to passive positions unless the intention is to turn all boards2 included in a batch, since the lifting devices 16 are then suitablyleft in their opened, active positions or alternatively are fixedlymounted on the third conveyor 15. During their movements in the opened,active position, the lifting devices follow a path which is defined by athird conveyor 15 and which makes an acute angle with the movementdirection of the first and second conveyors.

The present invention may be modified without departing from the spiritand scope of the appended claims.

What is claimed is:
 1. A method of turning boards which are transportedwith a longitudinal direction of said boards transverse to the directionof movement of a first conveyor provided with uniformly spaced conveyordogs, comprising: at least partly driving the boards by the front sidesof the dogs in abutment against the rear edges of the boards, whereinthe boards are moved forwards in the direction of movement in relationto the first conveyor such that the front edges of the boards arebrought to the region of the rear side of the next dog in the conveyor;engaging lifting devices with the undersides of those boards which areto be turned in the region of their front edges, wherein said liftingdevices are moved substantially synchronously with the conveyor;gradually raising the lifting devices; subjecting the boards to a forcein relation to the lifting device forwardly in their direction ofmovement, wherein the boards are turned over with their front edgefacing upwards/rearwards; and engaging at least one lifting device witheach board, such that said at least one lifting device follows the boardduring turning of the board.
 2. The method as claimed in claim 1,wherein the boards in their forward displacement relative to the firstconveyor are lifted slightly therefrom.
 3. The method as claimed inclaim 1, wherein the lifting devices are lowered after turning of theboards.
 4. The method as claimed in claim 1, wherein the lifting devicesare carried by a third conveyor which, in a vertical plane, makes anacute angle with the first conveyor.
 5. The method as claimed in claim1, wherein the boards in their forward movement relative to the firstconveyor and in their action relative to the lifting devices are actedon by at least one second conveyor.
 6. The method as claimed in claim 5,wherein the boards are lifted slightly by the second conveyor relativeto the first.
 7. An apparatus for turning boards comprising: a firstconveyor with uniformly spaced conveyor dogs for transport of theboards, with a longitudinal direction of said boards transverse to thedirection of movement of the conveyor; at least one second conveyorwhich is substantially parallel with the first and has an upper part ata slightly greater height than the upper part of the first conveyor, thesecond conveyor operating at greater speed of movement than the first;and a number of lifting devices which are disposed to be liftable so asto engage with the boards at forward portions of undersides of theboards, during turning of the boards with the front edge of said boardsupwards/rearwards, wherein the lifting devices are disposed on a thirdconveyor and are movable synchronously with the first conveyor.
 8. Theapparatus as claimed in claim 7, wherein the third conveyor, seen in avertical plane along its movement direction, makes an acute angle withthe first and the second conveyors.
 9. The apparatus as claimed in claim7, wherein at the end regions of the third conveyor, there are disposedguide rails or abutments for outward pivoting of the lifting devices toactive positions at the beginning of the conveyor and for downwardpivoting thereof to passive positions at the beginning of the conveyorand for downward pivoting thereof to passive positions at the end of theconveyor.
 10. The apparatus as claimed in claim 9, wherein the abutmentat the beginning of the third conveyor is movable between an activeposition where it pivots out passing lifting devices to their activepositions, and a passive position where lifting devices pass unhinderedin their passive positions.
 11. The apparatus as claimed in claim 7,wherein the first, the second and the third conveyors are disposedside-by-side.
 12. The apparatus as claimed in claim 7, wherein saidlifting devices are fixedly disposed on the third conveyor.
 13. Theapparatus as claimed in claim 7, wherein said lifting devices arepivotally secured on the third conveyor and are pivotal about pivot axeswhich are substantially parallel with parts of said third conveyor, thedistances between adjacent lifting devices substantially correspondingto the distance between adjacent dogs.
 14. The apparatus as claimed inclaim 7, wherein the free spaces between adjacent dogs are approximatelyof the same size as twice the width of those boards which are to beturned.